At 4.20 am on Monday, police were called to the six-storey Harbour Quays complex on East Quay Drive, Biggera Waters, following reports of an explosion and smoke coming from the basement.

Police found four cars alight in the building’s underground carpark.

Residents were quickly evacuated and there were no injuries, but all four cars and the building were extensively damaged.

Police believed the fire was deliberately lit using an accelerant.

A crime scene has been set up at the site of the fire, while investigations continue.